Dishwashing machine with spray tube rotational speed analyzer



R. V. LESLIE May 7, 1963 DISHWASHING MACHINE WITH SPRAY TUBE ROTATIONAL SPEED ANALYZER Filed QO'b- 9, 1961 Fig. 3

INVENTOR. Ralph M Leslie His Attorney HllllllllLllll lllllllllllllll llllll Fig.

United States Patent C) 3,088,474 DKSHWASHIIJG MACHINE WHTH SPRAY THEE RUTATIONAL SPEED ANALYZER Ralph V. Lesiie, Englewood, Uhio, assignar to General Motors Corporation, Detroit, Mich a corporation of Deiaware Filed st. 9, 1961, Ser. No. 143,755 6 Claims. (Cl. 134-113) This invention relates to a domestic appliance and more particularly to a speed analyzer for the spray tube of a dishwasher.

The dishwashing art has been troubled for some time with the problem of ascertaining the speed of spray tube rotation. The problem is made somewhat more complex by the fact that the interior of a dishwashing chamber is obscured by the steam and mist which is produced by the operating spray tube. Further, it is impossible to view the rotating spray tube when the dishwasher door is in its closed position.

Accordingly it is an object of this invention to provide a means whereby the rotating speed of a washing machine spray device can be ascertained while the machine is in operation.

More particularly, it is an object of this invention to provide a speed analyzer for a horizontally rotatable dishwasher spray tube in a washing chamber, said speed analyzer being comprised of a fluorescently segmented disc frictionally engageable and rotatable with the spray tube and an ultraviolet lamp outside of the chamber for casting light on the fluorescent segments as an indication of spray tube speed.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a generally schematic side sectional view of a dishwashing machine suitable for use with this invention;

FIGURE 2 is a fragmentary perspective view of the speed analyzer of this invention; and

FIGURE 3 is an enlarged elevational view of the strobe disc used with this invention.

In accordance with this invention and with reference to FIGURE 1 a dishwasher 1th is schematically set forth. The dishwasher is comprised of a casing 12 which defines a dishwashing or water distribution chamber 14 having a front opening 16. The bottom of the dishwashing chamber 14 is closed by a bulkhead or bottom wall 18 which has a depressed or sump area 20 in a central por tion thereof. The sump leads to a pump 22 which is operated by a motor 24. Within the dishwashing cham- .ber 14 a rotatably mounted spray tube 26 is positioned and interconnected with the pump 22 by way of a conduit 28. interposed in the fluid stream between the spray tube and the pump is a diverter valve 30 which may be selectively energized to direct the output of the pump either to the spray tube 26 or to a drain line 32. Water may be admitted to the sump 2th by means of a water valve 34 and a heater 36 is included in the sump for drying the dishes at the conclusion of the dishwashing cycle and for maintaining the temperature of the water during the dishwashing cycle.

Normally the front opening 16 of dishwashing chamber is closed by a door 38 which is hingedly mounted at 40 so that the door may be placed in a vertical position for closing the dishwashing chamber and in a horizontally disposed position for loading the dishwasher. However, for the purposes of this invention the front opening 16 of the dishwashing chamber is closed by a transparent 3,938,474 Patented May 7, 1963 ICC? panel of plastic or other suitable material 42 which is coextensive with the front opening 16. When the transparent panel 42 is installed as shown in FIGURE 1, the interior of the dishwashing chamber 14 becomes viewable. In this connection, when the dishwasher door 38 is in its open position as shown in FIGURE 1, a door switch 44 is actuated to deenergize the electrical components of the dishwasher.

The spray tube 26 is comprised of a cylindrical plastic tube having a closed front bearing end 48 and an open rear inlet end 50. A plurality of slots or perforations 52 are disposed along the length of the spray tube 26 and serve to direct the spray over supporting baskets 56 above and below the spray tube. At the rear of the spray tube 26 a swirl inducing header 58 is positioned for IC- tatably supporting the rear end 50 of the spray tube. A support rod 60 extends from the header 58 or the back wall of the dishwasher casing to the front end where a removable bearing 64 rotatably journals the front end 48 of the spray tube. The bearing 64 is provided with a threaded shaft and knob 66 which may be removed or unscrewed from the support 60 to remove the spray tube 26. For further details as to the construction of the spray tube and the manner in which the swirl of water through the center of the spray tube induces the rotation thereof, reference may be had to the patent to Abresch et al. 2,973,907 issued March 7, 1961. Thus when the motor 24 is energized and water exists in the sump 20 of the dishwasher, water will be directed through the conduit 28 to the swirl inducing spray header 58. As swirl is imparted to the pumped water the swirl will cause the spray tube 26 to rotate and the water pumped will issue from the slots 52 to thoroughly cover and cleanse the utensils supported in the baskets 56.

It has been found that the cleanability of the dishwasher 10 depends in large measure upon the proper distribution of washing fluid within the dishwashing chamber 12. This distribution depends upon the speed of rotation or r.p.m. of the spray tube 26. In the past it has been difficult to ascertain the correct speed of the spray tube due to the darkness of the interior of the dishwashing chamber and the obscurity of the spray tube due .to the swirling and spraying water within the chamber. The spraying water and the steam produced thereby so confuses the interior of the dishwashing chamber that normal stroboscopic methods to ascertain rotative speed are unavailing. This invention is directed to an improved manner for utilizing the stroboscopic theory which will overcome the problem created by an operating dishwasher and will still provide accurate data on the speed of spray tube rotation. The results of such tests can be used to evaluate the pump 22 and the motor 24. in order to insure that the proper amount of fluid is being recirculated between the sump 20 and the spray tube 26.

With reference to FIGURES 1 and 3 the spray tube analyzer is shown comprised of a black light 70 and a strobe disc 72. The strobe disc '72 may be formed of resilient rubber or other flexible material in the form of a washer having an outer circle or band 74 and an inner circle or band 76 concentric with the outer circle 74. On each of the bands 74 are painted or silk screened segments 78 and 80 respectively in an outstanding fluorescent paint. The segments 78 and 80 have been painted with a red fluorescent paint which has been found suitable for use in the obscure interior of an operating dishwasher. Interposed between the segments 78 and the segments 80 are spacing segments 82 and 84 which are formed of a subdued fluorescent paint such as yellow. Note that the segments 78 in the outer circle are shorter than the segments 80 on the inner circle 76. The reason for this construction is to provide for different speed indicators for the spray tube 26. For instance, the smaller outer colored segments, when appearing to stand still, indicate a slower speed than the larger segments on the inner circle.

The black light 70 is formed as a rectangular box-like structure having an open side 90 through which light may be directed from a black light bulb or ultraviolet lamp 92. One bulb found suitable for use with this invention is made by the Sylvania Company and is classified as F TH/BLB, Blacklite Blue and is 15 watts in size. The ultraviolet lamp is designed to operate on a 60-cycle frequency which cooperates with the strobe disc 72 as a means for indicating proper spray tube speed.

The manner in which the spray tube on the dishwasher can be checked for proper speed will now be explained more fully and with reference to FIGURE 2 of the drawings. The serviceman will first open the door 38 of the dishwasher and remove the spray tube bearing knob 66 which supports the front end of the spray tube. At this time it is careful not to disturb the rear end of the spray tube which is journaled in the swirl inducing housing 58. Next, place the strobe disc 72 over the end of the spray tube with the segmented design toward the front of the dishwasher. Mount the disc as close to the front of the spray tube as possible so that it does not block the spray issuing from the spray tube slots 52. Then replace the spray tube knob 66 so that the bearing portion 64 will extend into a cavity at the front end of the spray tube. Manually rotate the spray tube to assure that it turns freely and that the disc 72 does not touch the support bar 60 as it turns. (Ilose the door and start the dishwasher to energize the fill valve 34. After a normal fill is reached, open the door 38 and install the transparent panel 42 over the chamber opening.

It will be necessary to block the door switch 44 either mechanically or electrically so that the dishwasher can be operated with the door 38 open. Such overriding of the door switch safety feature is well within the skill of the art. With the motor 24 and the pump 22 in operation to pump water to the spray tube 26, a cleansing spray will be initiated within the dishwashing chamber 12. The spray will cloud the atmosphere inside the dishwashing chamber and will normally prevent observation of the spray tube speed. However, the operator can then hold the illuminated black light 70 against the front of the transparent panel 42 in a manner to shed its light on the front face of the strobe disc 72. It should be noted that the black light 70 can be plugged into any domestic power supply in order to provide a 60-cycle frequency. It should be recognized, however, that other frequencies and other sized fluorescent segments on the strobe disc could be used within the purview of this invention. The fluorescent markings on the strobe disc will react according to the spray tube speed and the 60-cycle frequency of the black light.

To understand the analysis provided by the strobe disc 72 and the black light 70 the following explanation is applicable. When the segments 78 on the outer circle and 80 on the inner circle are both blurred, this indicates that the speed of the spray tube is either too slow or too fast. When the colored segments in the outer circle appear to turn counterclockwise and the inner colored segments appear blurred, the spray tube is rotating only slightly below proper speed. As the segments in the outer circle stand still or do not rotate and the inner circle is blurred, the spray tube is rotating at the proper speed. Conversely, when the outer colored segments appear to be turning clockwise while the inner colored segment appears blurred, the spray tube is rotating slightly above proper speed. Lastly, when the segments in the outer circle are blurred and those in the inner circle appear stopped, the spray tube is operating at a higher than normal speed. Ordinarily, the serviceman need worry only about those situations wherein the spray tube is rotating too slowly. This will indicate some form of blockage or pump malfunction which causes a lower than normal pumping rate to the spray tube 26. This indicates a lack of proper 4 spray distribution within the dishwashing chamber and indicates that correction is necessary.

It should now be seen that an improved speed analyzer has been provided for a rotating spray tube in a dishwasher. The inherent problem of visibility in a steam clouded dishwashing chamber is overcome by the application of a strobe disc utilizing fluorescent segments in combination with a ultraviolet lamp which causes the segments to show through the cloudy atmosphere within the dishwasher.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In combination, casing means defining a dishwashing chamber having a front opening and a sump, means for supplying hot water to said sump, a transparent panel for closing said front opening, a horizontal, hollow cylindrical spray tube in said chamber having a closed front end extending toward said front opening, an open rear inlet end and a plurality of water distributing slots disposed along the length of said spray tube, a swirl-inducing header for rotatably mounting the rear inlet end of said spray tube, a pump connected to said sump for pumping water to said header for producing a swirl throughout the hollow of said spray tube to rotate said spray tube, a flexible circular disc frictionally engaging the front end of said spray tube for rotation therewith on the inside of said panel, said disc having radially inner and outer concentric circles of spaced fluorescent segments facing outwardly from said chamber toward said front opening, the segments on said inner circle being sized to represent one rotating speed for said spray tube and the segments on said outer circle being sized to represent another rotating speed for said spray tube, and a 60 cycle ultraviolet lamp positioned on the outside of said panel opposite said disc in a manner to shed light on said fluorescent segments, thereby to indicate by the apparent rotation of said segments the speed of said spray tube and the pumping rate of said pump.

2. In combination, casing means defining a chamber having an opening and a sump, means for supplying water to said sump, a transparent panel for closing said opening, a hollow cylindrical spray tube in said chamber having a closed first end extending toward said opening, an open second inlet end and a plurality of water distributing slots disposed along the length of said spray tube, a swirlinducing header for rotatably mounting the inlet end of said spray tube, a pump connected to said sump for pumping water to said header for producing a swirl throughout the hollow of said spray tube to rotate said spray tube, a circular disc frictionally engaging the first end of said spray tube for rotation therewith on the inside of said panel, said disc having radially inner and outer concentric circles of spaced fluorescent segments facing outwardly from said chamber toward said opening, the segments on said inner circle being sized to represent one rotating speed for said spray tube and the segments on said outer circle being sized to represent another rotating speed for i said spray tube, and a black light positioned on the outside of said panel opposite said disc in a manner to shed ultraviolet light on said fluorescent segments when connected to a domestic power supply, thereby to indicate by the apparent rotation of said segments the speed of said spray tube and the pumping rate of said pump.

3. In combination, casing means defining a chamber having an opening and a sump, means for supplying water to said sump, a transparent panel for closing said opening, a hollow spray tube in said chamber having a closed end extending toward said opening, an open inlet end and a water distributing slot disposed along the length of said spray tube, a swirl-inducing header for rotatably mounting the inlet end of said spray tube, a pump connected to said sump for pumping water to said header for producing a swirl throughout the hollow of said spray tube to rotate said spray tube and cause a spray in said chamber, a circular disc engaging the closed end of said spray tube for rotation therewith on the inside of said panel, said disc having a circle of spaced fluorescent segments facing outwardly from said chamber toward said opening, the segments being sized to represent one rotating speed for said spray tube, and an ultraviolet lamp positioned on the outside of said panel opposite said disc in a manner to shed light on said fluorescent segments when connected to a domestic power supply, thereby to indicate by the apparent rotation of said segments the speed of said spray tube and the pumping rate of said pump.

4. In combination, means forming a water distribution chamber having an opening, a transparent panel for closing said opening, a rotating horizontal spray tube in said chamber, and a speed analyzer for ascertaining the speed of said spray tube, said speed analyzer comprising a circular disc fitted snugly over said spray tube for rotation therewith in said chamber, said disc having radially inner and outer concentric circles of spaced fluorescent segments facing outwardly from said chamber in a manner to be seen through said transparent panel, the segments on said inner circle being sized to represent one rotating speed and the segments on said outer circle being sized to represent another rotating speed, and a 60 cycle ultraviolet lamp positioned outside of said chamber in a manner to shed its light through said transparent panel on said disc, thereby to indicate by the apparent movement of said segments the speed of said spray tube.

5. In combination, means forming a chamber having an opening, a transparent panel for closing said opening, a rotating spray device in said chamber, and a speed analyzer for ascertaining the speed of said spray device, said speed analyzer comprising a circular disc fastened to said spray device for rotation therewith in said chamber,

said disc having radially inner and outer concentric circles of spaced fluorescent segments facing outwardly from said chamber in a manner to be seen through said transparent panel, the segments on said inner circle being sized to represent one rotating speed and the segments on said outer circle being sized to represent another rotating speed, and a cycle ultraviolet lamp positioned outside of said chamber in a manner to shed its light on said disc, thereby to indicate by the apparent movement of said segments the speed of said spray device.

6. In combination, means forming a chamber having an opening, means including a transparent portion for closing said opening, a rotating spray device in said chamher, and a speed analyzer for ascertaining the speed of said spray device, said speed analyzer comprising a strobe member fastened for rotation with said spray device in said chamber, said strobe member having a circle of spaced fluorescent segments facing outwardly from said chamber in a manner to be seen through said transparent portion, the segments on said circle being sized to represent one rotating speed, and a cyclical lamp positioned outside of said chamber in a manner to shed its light on said strobe member and compatible with the fluorescence of said segments, thereby to indicate by the apparent movement of said segments the speed of said spray device.

References Cited in the file of this patent UNITED STATES PATENTS 1,877,713 Beck Sept. 13, 1932 2,119,627 Kriek June 7, 1938 2,691,380 Bartos Oct. 12, 1954 2,734,520 Abresch Feb. 14, 1956 3,013,569 Sterczala Dec. 19, 1961 

6. IN COMBINATION, MEANS FORMING A CHAMBER HAVING AN OPENING, MEANS INCLUDING A TRANSPARENT PORTION FOR CLOSING SAID OPENING, A ROTATING SPRAY DEVICE IN SAID CHAMBER, AND A SPEED ANALYZER FOR ASCERTAINING THE SPEED OF SAID SPRAY DEVICE, SAID SPEED ANALYZER COMPRISING A STROBE MEMBER FASTENED FOR ROTATION WITH SAID SPRAY DEVICE IN SAID CHAMBER, SAID STROBE MEMBER HAVING A CIRCLE OF SPACED FLUORESCENT SEGMENTS FACING OUTWARDLY FROM SAID CHAMBER IN A MANNER TO BE SEEN THROUGH SAID TRANSPARENT PORTION, THE SEGMENTS ON SAID CIRCLE BEING SIZED TO REPRESENT ONE ROTATING SPEED, AND A CYCLICAL LAMP POSITIONED OUTSIDE OF SAID CHAMBER IN A MANNER TO SHED ITS LIGHT ON 